Overweight and obesity are among the greatest public health challenges of the century. A major cause is a disturbed energy balance (i.e., energy intake > energy expenditure). From a health interventionist viewpoint, focusing on the energy balance that is mainly determined by physical activity (PA), sedentary behaviour (SB), dietary intake and sleep, is promising as these behaviours

can be affected by behaviour change interventions. This project will use a holistic approach and focus simultaneously on PA, SB, dietary behaviours and sleep and its time-and context-dependent determinants in 55-75 year old adults, as prevalence of

overweight and obesity is highest in this age group. 

Two studies will be conducted. First, using data of the Asklepios study, the contemporaneous covariance of PA, SB, dietary behaviours and sleep will be examined. In a second intensive longitudinal observational study with six measurement bursts within one year, continuous monitoring of the four health behaviours will be done and fine-grained determinants will be assessed using ecological momentary assessment. The purpose is to understand the temporal dynamics of the behaviours and the micro-temporal processes underlying these behaviours. The ultimate project goal is to inform more personalized, effective health behaviour intervention development.